A newly formed political committee that is not required to immediately disclose its donors has spent $480,000 on a major television advertising buy days before the mayoral election on behalf of state Representative Martin J. Walsh, according to a report filed this week with the state.

The political action committee, One Boston, is not obliged to identify its financial backers until January, after voters cast ballots in this Tuesday’s election. The only name listed on the committee’s paperwork is Jocelyn Hutt, a 55-year-old woman from Congreve Street in Roslindale. She has not voted in three of Boston’s past four municipal elections, according to city records.

The surge of outside money in the waning days of the campaign underscores the role that political committees are playing in the first wide-open mayoral race in a generation in Boston. Walsh’s opponent, Councilor at Large John R. Connolly, has also benefited from such money, but at much lower levels. Outside groups have spent three times more on Walsh than on Connolly.

One Boston is the second newly formed political committee that has flooded the mayoral race with outside money to air television commercials for Walsh. The other, American Working Families, established a political committee in Massachusetts in July and listed the address of a post office box at a UPS store in Alexandria, Va., according to state records. American Working Families has spent $1.1 million for Walsh. The only name associated with the group is Bud Jackson, a Democratic media consultant who has repeatedly declined to disclose donors before the election.

Walsh said the organization should be transparent, but added he had no information about the group, including its donor base.

“They should disclose their donors, anybody, yeah,” Walsh said. “But I have no idea who they are. This is the first I’ve heard of it.”

Two education groups have spent $713,000 supporting Connolly. The main group spending money on behalf of the city councilor, Democrats for Education Reform, established a political committee in Massachusetts in 2011 and has supported other candidates.

In addition to the two new political committees, labor unions have also invested heavily in Walsh, bringing total outside spending for the legislator to $2.4 million. His official campaign had only spent $1.7 million by Oct. 15, according to the most recent bank filing.

Outside groups are legally barred from coordinating with a candidate’s official campaign. American Working Families had cameras at Walsh’s party the night of September’s preliminary election and used footage in a commercial. Reporters saw cameras from an outside group at a Walsh rally with women on Saturday. Walsh spokeswoman Kate Norton said that the campaign did extensive public outreach before the women’s event. “The event was open to the public and press and was weeks in the making,” Norton said in an e-mail. “We cannot and do not coordinate with groups like this, and we did not invite them.”

Political action committees spending money in the mayoral race are required to report expenditures within 24 hours in the final days before an election. But the state law allows donors to remain confidential until January. The state’s top campaign finance officials have asked the groups to voluntarily release names before the mayoral election.

“We are strongly recommending, in the spirit of disclosure, that contributors [to the political committees] be disclosed,” Michael Sullivan, director of the state Office of Campaign and Political Finance, wrote in a letter dated Sept. 11.

One Boston filed paperwork with the state Oct. 24 to form a political action committee and listed Hutt as both chairwoman and treasurer. The committee’s television ad for Walsh began airing Wednesday.

Hutt did not respond to questions about Walsh’s call for her committee to release its donors list. She has not contributed to political candidates in Massachusetts in recent years, according to state records. Hutt is a senior account manager for the East Coast division of DRS and Associates, which describes itself as a boutique public relations, advertising, and marketing agency specializing in luxury brands, its website says.

“I am not doing any media interviews,” Hutt said in an e-mail. “But to reiterate: Donors will be disclosed on the next regularly scheduled [political action committee] report” in January.

American Working Families has also refused to release its donors, although several local labor unions have reported giving the group money, records show. Jackson, the media consultant associated with the group, said in e-mail Thursday that he would not heed the request from state officials or Walsh to be more transparent.

“We are not legally allowed to take direction from a candidate,” Jackson said. “We look forward to disclosing our donors as the law requires.”

The other outside groups backing Walsh have been funded by organized labor. That includes Working America, which is the political arm of the national AFL-CIO, and individual labor unions.

Connolly campaign spokeswoman Natasha Perez said that Walsh is counting on millions of dollars from outside groups to buy this election for him.

“This is even more evidence that Representative Walsh will be beholden to special interests rather than being the independent mayor that Boston deserves,” Perez said in e-mail.

Democrats for Education Reform, the group supporting Connolly, filed a required report at the end of June showing roughly 100 donations from individuals, ranging from $5
to $100. The largest amount of its money came from Education Reform Advocacy Now, a New York nonprofit that donated $25,000.

The board chairman is Charles H. Ledley, a hedge fund analyst who was a consultant at Bain & Company, where former governor Mitt Romney had worked. The nonprofit donated another $80,000 in July and August, records show.

Democrats for Education Reform stopped spending money for Connolly in September at the candidate’s request, but it began spending again earlier this month as outside spending for Walsh reached into the millions. Democrats for Education Reform said it did not have plans to release the names of donors until January.

A representative of the group said it was following the lead of outside political committees backing Walsh. “They decided to let outside groups in,” said Liam Kerr. “They are setting the rules.”

Joshua Miller of the Globe staff contributed to this report. Andrew Ryan can be reached at acryan@globe.com.

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